Catálogo de publicaciones - libros

Nowadays it is widely recognized the crucial role played in the software development process by the analysis of extra-functional properties (and especially performance) at the architectural level. To foster this kind of quantitative analysis we envisage the need to transform the performance model generation and analysis into a rigorous and sound discipline. To this end we intend to exploit the knowledge (acquired by other disciplines) in the area of model transformation, and import both reasoning and methodologies in the software performance engineering. In this paper we investigate the area of performance model derivation and analysis focusing on model transformation; we propose an initial taxonomy for the area of performance analysis at software architecture level and we delineate our suggestions towards a software performance model driven engineering.

Making software developers work towards a common goal may be likened to herding cats. If we further spread developers around the globe, we run increased risks of being unable to design and impose coherent software architectures on projects, potentially leading to lower quality of the resulting systems. Based on our experiences in a large, distributed research and development project, , we propose that employing techniques from active user involvement in general (and from participatory design in particular) may help in designing and sharing quality software architectures. In particular, we present the technique in which a group of architects visit development locations in order to engage developers and end users in software architecture work. We argue that using techniques such as these may potentially lead to higher quality of software architectures in particular for systems developed in a distributed setting.

When engineering complex and distributed software and hardware systems (increasingly used in many sectors, such as manufacturing, aerospace, transportation, communication, energy and health-care), dependability has became a must, since failures can have economics consequences and can also endanger human life.

Software Architectures (SA) can help improving the overall system dependability, providing a system blueprint that can be validated and that can guide all phases of the system development. Even if much work has been done on this direction, three important topics require major investigation: how different analysis techniques can be integrated together, how results obtained with SA-based analysis can be related to requirements and coding, and how to integrate new methodologies in the industrial software development life-cycle.

In this paper we propose an architecture-centric analysis process which allows formal analysis driven by model-based architectural specifications. This analysis process satisfies the industrial requirements, since it is tool supported and based on semi-formal (UML-based) specifications.

Short innovation cycles in software and hardware make architecture design a key issue in future development processes for embedded systems. The basis for architectural design decisions is a transparent architecture evaluation.

Our model-based approach supports a uniform representation of hierarchies of quality attributes and an integration of different architecture evaluation techniques and methods. We present a metamodel for architecture evaluation as a basis for the precise description of the quality attribute structure and the evaluation methodology. By modelling architecture evaluation, the relationships between architectural elements and quality attributes and interdependencies between quality attributes can be represented and investigated. Thereby, the architecture exploration process with its evaluations, decisions, and optimizations is made explicit, traceable, and analyzable.

Performance predictions based on design documents aim at improving the quality of software architectures. In component-based architectures, it is difficult to specify the performance of individual components, because it depends on the deployment context of a component, which may be unknown to its developers. The way components are used influences the perceived performance, but most performance prediction approaches neglect this influence. In this paper, we present a specification notation based on annotated UML diagrams to explicitly model the influence of parameters on the performance of a software component. The UML specifications are transformed into a stochastical model that allows the prediction of response times as distribution functions. Furthermore, we report on a case study performed on an online store. The results indicate that more accurate predictions could be obtained with the newly introduced specification and that the method was able to support a design decision on the architectural level in our scenario.

For two years, we have been involved in a challenging project to develop a new architecture for an industrial transportation system. The motivating quality attributes to develop this innovative architecture were flexibility and openness. Taking these quality attributes into account, we proposed a decentralized architecture using multiagent systems (MASs). A MAS consists of multiple autonomous entities that coordinate with each other to achieve decentralized control. The typical advantages attributed to such decentralized architecture are flexibility and openness, the motivating quality attributes to apply MAS in this case.

The Architecture Tradeoff Analysis Method (ATAM) was used to provide insights wether our architecture meets the expected flexibility and openness, and to identify tradeoffs with other quality attributes. Applying the ATAM proved to be a valuable experience. One of the main outcome of applying the ATAM was the identification of a tradeoff between flexibility and communication load that results from the use of a decentralized architecture.

This paper describes our experiences in applying the ATAM to a MAS architecture, containing both the main outcomes of the evaluation and a critical reflection on the ATAM itself.

To deliver complex functionalities in a cost effective manner, embedded software should ideally be developed with standardized interoperable components. At the same time, most of these embedded systems must be demonstrably safe and reliable. This paper aims to extend SaveCCM, a modelling language for component-based embedded systems, with standard safety evaluation models. Based on this extension, failure and hazard probabilities can be estimated early in the development process and can be used to check if a system can fulfil its safety requirements. The procedure of the safety evaluation is demonstrated with the case study of a computer assisted braking system.